Can adjustable glasses help kids in poor countries?

For many children in poor nations, a simple pair of glasses can be out of reach. But a new study suggests relatively cheap specs that people can adjust themselves hold some promise.

The study, reported in the journal Ophthalmology, looked at the usefulness of "self-refracting" glasses for adolescents with vision problems, mostly nearsightedness.

The glasses are designed so that the wearer can adjust them to the right strength without the need for eye professionals, who are scarce in developing parts of the world. In parts of sub-Saharan Africa, for example, there is just one optometrist for every 1 million people.

Made under the name Adspecs, the glasses are already in use. About 30,000 adults in developing nations have received them so far, according to the Center for Vision in the Developing World - a group directed by Adspecs inventor Dr. Joshua D. Silver, a physicist at Oxford University in the UK.

But it hadn't been clear whether children and teenagers could feasibly use the specs. So in the new study, Silver and colleagues in China, the UK and U.S. had 554 Chinese students aged 12 to 17 years try them out.

The researchers compared the students' ability to self-correct their vision - under the supervision of their teachers, who had been shown how to use the glasses - against the results of a professional eye exam.

The adjustable glasses work via special lenses made of a clear membrane filled with silicon oil and held between two plastic discs. The wearer can change the amount of oil in the lenses using a removable syringe and dial that attach to the glasses' frame. Adding or removing oil changes the curvature of the lenses, which alters their strength.

Among kids in the current study, just over 92 percent were able to correct their nearsightedness using the glasses. That compared with a nearly 100-percent rate when the students were given professional eye exams.

"What we have proven is the basic principle," said Silver in an e-mail to Reuters Health. "The large majority of teenaged children in an area where poor vision from uncorrected refractive error is common can achieve vision sufficient to meet the demands of the classroom."

But many questions remain, the researchers say - including how well the glasses would work for children in the real world, over the long term.

The specs also have their limits. For example, they cannot correct astigmatism, a common eye problem that is usually mild but can cause blurred vision in some cases. Nor are they known for their stylish looks: They are large, round, thick-framed and vaguely Harry Potter-esque - although Silver's Center for Vision says the aesthetics should improve as the technology does.

And that is a major barrier to the glasses being put into wide use for now, according to Dr. Thomas S. Shane, an eye doctor with Bascom Palmer Eye Institute in Miami who was not involved in the study.